AC Test Transformers — Cylinder & Tank Type
Applied-voltage sources from 50 kV to 2,250 kV in cascade
An applied-voltage test needs a source that holds its voltage while the object misbehaves. Corona starts, a wet test loads the surface, a pollution layer draws current, and the reading still has to stay where you set it. Atlas Energy supplies both cylinder and tank-type AC test transformers, so the source is chosen for the object instead of the object being fitted around the source.
A single cylinder module covers 50 kV / 0.1 A up to 750 kV / 2 A, and modules cascade to 2,250 kV and 6 A. Tank types reach 1,000 kV and 50 A, with high-current variants at 200 kV / 20 A and 300 kV / 30 A. Input is 0.22, 0.38, 0.4, 0.6, 3, 6 or 10 kV. Cylinder duty is one hour on and one hour off, eight times a day; tank types support longer duty. The design is low-PD and under 2 pC is achievable in a complete configured system. Weight runs from 80 kg to 200,000 kg depending on rating.
Why it matters
Under 2 pC in a complete configured system means the source is not what limits your partial discharge sensitivity.
Cylinder modules cascade to 2,250 kV, so a laboratory can start at one voltage level and add stages instead of replacing the source.
Tank types stack where floor space is short and carry longer duty cycles than a cylinder design.
Stable voltage under changing load is what makes corona, wet and pollution tests repeatable rather than argumentative.
Over-voltage, over-current, arc detection and object-breakdown trip, with optional automatic PD supervision and trip, protect the object when its insulation fails.
Ratings
Cylinder type — single module: 50 kV / 0.1 A up to 750 kV / 2 A
Cylinder type — cascaded: Up to 2,250 kV and 6 A
Tank type: Up to 1,000 kV and 50 A; high-current variants 200 kV / 20 A and 300 kV / 30 A
Input voltage: 0.22 / 0.38 / 0.4 / 0.6 / 3 / 6 / 10 kV
Duty: 1 h on / 1 h off, 8 times per day (cylinder); longer duty available on tank type
Partial discharge: Low-PD design; <2 pC achievable in a complete configured system
Weight: 80 kg to 200,000 kg depending on rating
Protection: Over-voltage, over-current, arc detection and object-breakdown trip; optional automatic PD supervision with trip
Extended range
Cylinder type — where it fits: Medium-capacitance objects; tests needing stable voltage under changing load such as corona, wet and pollution tests; inductive objects like inductive VTs
Tank type — where it fits: Low and medium-capacitance objects, inductive objects, longer duty cycles, stackable modules where floor space is limited
System scope: Test transformer, regulating transformer, power line filter, compensating reactor, coupling capacitor / HV divider / HV filter, damping resistor, control and measuring system; optional PD detector, capacitance and tan δ bridge, air cushions and water terminations
Standards
IEEE Std 4
IEC 60060-1
IEC 60076-3
Applications
Applied-voltage tests in transformer and switchgear factories
Insulator and bushing type testing
Pollution and wet withstand testing
Test laboratory build-outs
Questions engineers ask
Cylinder type or tank type — which should I specify? Cylinder types suit medium-capacitance objects and tests that need stable voltage under changing load, such as corona, wet and pollution testing, and inductive objects like inductive voltage transformers. Tank types suit low and medium-capacitance objects, inductive objects, longer duty cycles, and installations where modules have to stack because floor space is limited.
What is supplied with the test transformer? A configured system includes the test transformer, regulating transformer, power line filter, compensating reactor, coupling capacitor, HV divider and HV filter, damping resistor, and the control and measuring system. A PD detector, a capacitance and tan δ bridge, air cushions and water terminations are added where the test bay calls for them.
